1.5 IEEE Std 754 Considerations

The Institute of Electrical and Electronics Engineers (IEEE) ANSI/IEEE Std 754-1985, IEEE Standard for Binary Floating-Point Arithmetic data types include denormalized numbers (very close to zero). The standard supports the concept of "Not-a-Number" or NaN to represent indeterminate quantities, and uses plus infinity or minus infinity (so that they behave in arithmetic) like the mathematical infinities. Whenever a DPML routine produces an overflow or indeterminate condition, it generates an infinity or NaN value.

All DPML routines, except one, return a NaN result when presented with a NaN input. The only exception is pow(NaN,0) = 1 in ANSI C.